[PATCH 1/1] elevator: a removal of not-necessary mem-fetches

From: Ananiev, Leonid I
Date: Thu Dec 01 2005 - 09:35:52 EST

>From Leonid Ananiev

The patch eliminates 1 of 3 additional main memory readings
in 17 indirrect io-scheduler function calls.
The "elevator" structure (~100 bytes) is embedded in request queue
structure.

Signed-off-by: Leonid Ananiev <leonid.i.ananiev@xxxxxxxxx>
---
This patch is applied and tested kernel 2.6.15-rc2.
Online switching between io schedulers was introduced in
Linux 2.6.10 but performance degradation is marked
on Itanium as a result. A cause of degradation is in more steps
for indirect IO scheduler function calls.

Sysbench fileio benchmark throughput on IPF was increased by 8% for
noop elevator after patching.
sysbench --test=fileio --file-test-mode=rndrw --num-threads=16 \
--file-total-size=1500M --max-requests=150000
Main memory size was decreased by kernel boot parameter mem=1G

One of functions object codes before and after patching are
<elv_merge_requests>: <elv_merge_requests>:
alloc r36=ar.pfs,9,6,0 adds r3=24,r32
adds r8=24,r32 mov r35=b0
mov r35=b0 adds r8=740,r32
adds r9=644,r32 mov r37=r1
mov r37=r1 mov r40=r34;;
mov r40=r34;; nop.m 0x0
nop.m 0x0 mov.i ar.pfs=r36
mov.i ar.pfs=r36 nop.b 0x0
nop.b 0x0 ld8 r2=[r3]
ld8 r3=[r8] mov r38=r32
mov r38=r32 mov r39=r33;;
mov r39=r33 adds r14=16,r2
adds r16=16,r32 adds r11=16,r32
nop.f 0x0 mov b0=r35;;
mov b0=r35;; nop.m 0x0
ld8 r2=[r3];; ld8 r14=[r14]
adds r14=16,r2 nop.b 0x0;;
nop.i 0x0;; nop.m 0x0
ld8 r14=[r14];; cmp.eq p6,p7=0,r14
nop.m 0x0 br.cond.dpnt.few
cmp.eq p6,p7=0,r14
nop.b 0x0
nop.b 0x0
br.cond.dpnt.few


diff -urpN -X a/Documentation/dontdiff \
a/block/as-iosched.c b/block/as-iosched.c
--- a/block/as-iosched.c 2005-11-27 14:46:09.000000000 -0800
+++ b/block/as-iosched.c 2005-11-24 14:45:51.000000000 -0800
@@ -625,7 +625,7 @@ static void as_antic_stop(struct as_data
static void as_antic_timeout(unsigned long data)
{
struct request_queue *q = (struct request_queue *)data;
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
unsigned long flags;

spin_lock_irqsave(q->queue_lock, flags);
@@ -968,7 +968,7 @@ static void update_write_batch(struct as
*/
static void as_completed_request(request_queue_t *q, struct request *rq)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(rq);

WARN_ON(!list_empty(&rq->queuelist));
@@ -1028,7 +1028,7 @@ static void as_remove_queued_request(req
{
struct as_rq *arq = RQ_DATA(rq);
const int data_dir = arq->is_sync;
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;

WARN_ON(arq->state != AS_RQ_QUEUED);

@@ -1168,7 +1168,7 @@ static void as_move_to_dispatch(struct a
*/
static int as_dispatch_request(request_queue_t *q, int force)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq;
const int reads = !list_empty(&ad->fifo_list[REQ_SYNC]);
const int writes = !list_empty(&ad->fifo_list[REQ_ASYNC]);
@@ -1366,7 +1366,7 @@ as_add_aliased_request(struct as_data *a
*/
static void as_add_request(request_queue_t *q, struct request *rq)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(rq);
struct as_rq *alias;
int data_dir;
@@ -1449,7 +1449,7 @@ static void as_deactivate_request(reques
*/
static int as_queue_empty(request_queue_t *q)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;

return list_empty(&ad->fifo_list[REQ_ASYNC])
&& list_empty(&ad->fifo_list[REQ_SYNC]);
@@ -1484,7 +1484,7 @@ static struct request *as_latter_request
static int
as_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
sector_t rb_key = bio->bi_sector + bio_sectors(bio);
struct request *__rq;
int ret;
@@ -1527,7 +1527,7 @@ out:

static void as_merged_request(request_queue_t *q, struct request *req)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(req);

/*
@@ -1568,7 +1568,7 @@ static void as_merged_request(request_qu
static void as_merged_requests(request_queue_t *q, struct request *req,
struct request *next)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(req);
struct as_rq *anext = RQ_DATA(next);

@@ -1656,7 +1656,7 @@ static void as_work_handler(void *data)

static void as_put_request(request_queue_t *q, struct request *rq)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(rq);

if (!arq) {
@@ -1678,7 +1678,7 @@ static void as_put_request(request_queue
static int as_set_request(request_queue_t *q, struct request *rq,
struct bio *bio, gfp_t gfp_mask)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = mempool_alloc(ad->arq_pool, gfp_mask);

if (arq) {
@@ -1700,7 +1700,7 @@ static int as_set_request(request_queue_
static int as_may_queue(request_queue_t *q, int rw, struct bio *bio)
{
int ret = ELV_MQUEUE_MAY;
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct io_context *ioc;
if (ad->antic_status == ANTIC_WAIT_REQ ||
ad->antic_status == ANTIC_WAIT_NEXT) {
diff -urpN -X a/Documentation/dontdiff \
a/block/cfq-iosched.c b/block/cfq-iosched.c
--- a/block/cfq-iosched.c 2005-11-27 14:46:09.000000000 -0800
+++ b/block/cfq-iosched.c 2005-11-24 14:45:51.000000000 -0800
@@ -342,7 +342,7 @@ static inline void cfq_schedule_dispatch

static int cfq_queue_empty(request_queue_t *q)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;

return !cfqd->busy_queues;
}
@@ -643,14 +643,14 @@ out:

static void cfq_activate_request(request_queue_t *q, struct request *rq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;

cfqd->rq_in_driver++;
}

static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;

WARN_ON(!cfqd->rq_in_driver);
cfqd->rq_in_driver--;
@@ -668,7 +668,7 @@ static void cfq_remove_request(struct re
static int
cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct request *__rq;
int ret;

@@ -692,7 +692,7 @@ out:

static void cfq_merged_request(request_queue_t *q, struct request *req)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct cfq_rq *crq = RQ_DATA(req);

cfq_del_crq_hash(crq);
@@ -928,7 +928,7 @@ static int cfq_arm_slice_timer(struct cf

static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct cfq_queue *cfqq = crq->cfq_queue;

cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq);
@@ -1128,7 +1128,7 @@ cfq_forced_dispatch(struct cfq_data *cfq
static int
cfq_dispatch_requests(request_queue_t *q, int force)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct cfq_queue *cfqq;

if (!cfqd->busy_queues)
@@ -1676,7 +1676,7 @@ cfq_crq_enqueued(struct cfq_data *cfqd,

static void cfq_insert_request(request_queue_t *q, struct request *rq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct cfq_rq *crq = RQ_DATA(rq);
struct cfq_queue *cfqq = crq->cfq_queue;

@@ -1842,7 +1842,7 @@ __cfq_may_queue(struct cfq_data *cfqd, s

static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct task_struct *tsk = current;
struct cfq_queue *cfqq;

@@ -1865,7 +1865,7 @@ static int cfq_may_queue(request_queue_t

static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct request_list *rl = &q->rq;

if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) {
@@ -1886,7 +1886,7 @@ static void cfq_check_waiters(request_qu
*/
static void cfq_put_request(request_queue_t *q, struct request *rq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct cfq_rq *crq = RQ_DATA(rq);

if (crq) {
@@ -1913,7 +1913,7 @@ static int
cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
gfp_t gfp_mask)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct task_struct *tsk = current;
struct cfq_io_context *cic;
const int rw = rq_data_dir(rq);
@@ -1986,7 +1986,7 @@ queue_fail:
static void cfq_kick_queue(void *data)
{
request_queue_t *q = data;
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
unsigned long flags;

spin_lock_irqsave(q->queue_lock, flags);
diff -urpN -X a/Documentation/dontdiff\
a/block/deadline-iosched.c b/block/deadline-iosched.c
--- a/block/deadline-iosched.c 2005-11-27 14:46:09.000000000 -0800
+++ b/block/deadline-iosched.c 2005-11-24 14:45:51.000000000 -0800
@@ -276,7 +276,7 @@ deadline_find_first_drq(struct deadline_
static void
deadline_add_request(struct request_queue *q, struct request *rq)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(rq);

const int data_dir = rq_data_dir(drq->request);
@@ -298,7 +298,7 @@ deadline_add_request(struct request_queu
static void deadline_remove_request(request_queue_t *q, struct request *rq)
{
struct deadline_rq *drq = RQ_DATA(rq);
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;

list_del_init(&drq->fifo);
deadline_del_drq_rb(dd, drq);
@@ -308,7 +308,7 @@ static void deadline_remove_request(requ
static int
deadline_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct request *__rq;
int ret;

@@ -352,7 +352,7 @@ out:

static void deadline_merged_request(request_queue_t *q, struct request *req)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(req);

/*
@@ -374,7 +374,7 @@ static void
deadline_merged_requests(request_queue_t *q, struct request *req,
struct request *next)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(req);
struct deadline_rq *dnext = RQ_DATA(next);

@@ -471,7 +471,7 @@ static inline int deadline_check_fifo(st
*/
static int deadline_dispatch_requests(request_queue_t *q, int force)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
const int reads = !list_empty(&dd->fifo_list[READ]);
const int writes = !list_empty(&dd->fifo_list[WRITE]);
struct deadline_rq *drq;
@@ -567,7 +567,7 @@ dispatch_request:

static int deadline_queue_empty(request_queue_t *q)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;

return list_empty(&dd->fifo_list[WRITE])
&& list_empty(&dd->fifo_list[READ]);
@@ -659,7 +659,7 @@ static int deadline_init_queue(request_q

static void deadline_put_request(request_queue_t *q, struct request *rq)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(rq);

mempool_free(drq, dd->drq_pool);
@@ -670,7 +670,7 @@ static int
deadline_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
gfp_t gfp_mask)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq;

drq = mempool_alloc(dd->drq_pool, gfp_mask);
diff -urpN -X a/Documentation/dontdiff\
a/block/elevator.c b/block/elevator.c
--- a/block/elevator.c 2005-11-27 14:46:09.000000000 -0800
+++ b/block/elevator.c 2005-11-24 20:19:37.000000000 -0800
@@ -121,17 +121,15 @@ static struct elevator_type *elevator_ge
return e;
}

-static int elevator_attach(request_queue_t *q, struct elevator_type *e,
- struct elevator_queue *eq)
+static int elevator_attach(request_queue_t *q, struct elevator_type *e)
{
int ret = 0;
+ struct elevator_queue *eq;

- memset(eq, 0, sizeof(*eq));
+ eq = &q->elevator;
eq->ops = &e->ops;
eq->elevator_type = e;

- q->elevator = eq;
-
if (eq->ops->elevator_init_fn)
ret = eq->ops->elevator_init_fn(q, eq);

@@ -170,7 +168,6 @@ __setup("elevator=", elevator_setup);
int elevator_init(request_queue_t *q, char *name)
{
struct elevator_type *e = NULL;
- struct elevator_queue *eq;
int ret = 0;

INIT_LIST_HEAD(&q->queue_head);
@@ -187,15 +184,8 @@ int elevator_init(request_queue_t *q, ch
if (!e)
return -EINVAL;

- eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL);
- if (!eq) {
- elevator_put(e);
- return -ENOMEM;
- }
-
- ret = elevator_attach(q, e, eq);
+ ret = elevator_attach(q, e);
if (ret) {
- kfree(eq);
elevator_put(e);
}

@@ -209,7 +199,6 @@ void elevator_exit(elevator_t *e)

elevator_put(e->elevator_type);
e->elevator_type = NULL;
- kfree(e);
}

/*
@@ -249,7 +238,7 @@ void elv_dispatch_sort(request_queue_t *

int elv_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
int ret;

if (q->last_merge) {
@@ -268,7 +257,7 @@ int elv_merge(request_queue_t *q, struct

void elv_merged_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

if (e->ops->elevator_merged_fn)
e->ops->elevator_merged_fn(q, rq);
@@ -279,7 +268,7 @@ void elv_merged_request(request_queue_t
void elv_merge_requests(request_queue_t *q, struct request *rq,
struct request *next)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

if (e->ops->elevator_merge_req_fn)
e->ops->elevator_merge_req_fn(q, rq, next);
@@ -290,7 +279,7 @@ void elv_merge_requests(request_queue_t

void elv_requeue_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

/*
* it already went through dequeue, we need to decrement the
@@ -318,14 +307,14 @@ void elv_requeue_request(request_queue_t
static void elv_drain_elevator(request_queue_t *q)
{
static int printed;
- while (q->elevator->ops->elevator_dispatch_fn(q, 1))
+ while (q->elevator.ops->elevator_dispatch_fn(q, 1))
;
if (q->nr_sorted == 0)
return;
if (printed++ < 10) {
printk(KERN_ERR "%s: forced dispatching is broken "
"(nr_sorted=%u), please report this\n",
- q->elevator->elevator_type->elevator_name, q->nr_sorted);
+ q->elevator.elevator_type->elevator_name, q->nr_sorted);
}
}

@@ -390,7 +379,7 @@ void __elv_add_request(request_queue_t *
* rq cannot be accessed after calling
* elevator_add_req_fn.
*/
- q->elevator->ops->elevator_add_req_fn(q, rq);
+ q->elevator.ops->elevator_add_req_fn(q, rq);
break;

default:
@@ -423,7 +412,7 @@ static inline struct request *__elv_next
struct request *rq;

if (unlikely(list_empty(&q->queue_head) &&
- !q->elevator->ops->elevator_dispatch_fn(q, 0)))
+ !q->elevator.ops->elevator_dispatch_fn(q, 0)))
return NULL;

rq = list_entry_rq(q->queue_head.next);
@@ -450,7 +439,7 @@ struct request *elv_next_request(request

while ((rq = __elv_next_request(q)) != NULL) {
if (!(rq->flags & REQ_STARTED)) {
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

/*
* This is the first time the device driver
@@ -526,7 +515,7 @@ void elv_dequeue_request(request_queue_t

int elv_queue_empty(request_queue_t *q)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

if (!list_empty(&q->queue_head))
return 0;
@@ -539,7 +528,7 @@ int elv_queue_empty(request_queue_t *q)

struct request *elv_latter_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

if (e->ops->elevator_latter_req_fn)
return e->ops->elevator_latter_req_fn(q, rq);
@@ -548,7 +537,7 @@ struct request *elv_latter_request(reque

struct request *elv_former_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

if (e->ops->elevator_former_req_fn)
return e->ops->elevator_former_req_fn(q, rq);
@@ -558,7 +547,7 @@ struct request *elv_former_request(reque
int elv_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
gfp_t gfp_mask)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

if (e->ops->elevator_set_req_fn)
return e->ops->elevator_set_req_fn(q, rq, bio, gfp_mask);
@@ -569,7 +558,7 @@ int elv_set_request(request_queue_t *q,

void elv_put_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

if (e->ops->elevator_put_req_fn)
e->ops->elevator_put_req_fn(q, rq);
@@ -577,7 +566,7 @@ void elv_put_request(request_queue_t *q,

int elv_may_queue(request_queue_t *q, int rw, struct bio *bio)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

if (e->ops->elevator_may_queue_fn)
return e->ops->elevator_may_queue_fn(q, rw, bio);
@@ -587,7 +576,7 @@ int elv_may_queue(request_queue_t *q, in

void elv_completed_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

/*
* request is released from the driver, io must be done
@@ -601,7 +590,7 @@ void elv_completed_request(request_queue

int elv_register_queue(struct request_queue *q)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;

e->kobj.parent = kobject_get(&q->kobj);
if (!e->kobj.parent)
@@ -616,7 +605,7 @@ int elv_register_queue(struct request_qu
void elv_unregister_queue(struct request_queue *q)
{
if (q) {
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
kobject_unregister(&e->kobj);
kobject_put(&q->kobj);
}
@@ -675,14 +664,7 @@ EXPORT_SYMBOL_GPL(elv_unregister);
*/
static void elevator_switch(request_queue_t *q, struct elevator_type *new_e)
{
- elevator_t *old_elevator, *e;
-
- /*
- * Allocate new elevator
- */
- e = kmalloc(sizeof(elevator_t), GFP_KERNEL);
- if (!e)
- goto error;
+ elevator_t old_elevator;

/*
* Turn on BYPASS and drain all requests w/ elevator private data
@@ -713,7 +695,7 @@ static void elevator_switch(request_queu
/*
* attach and start new elevator
*/
- if (elevator_attach(q, new_e, e))
+ if (elevator_attach(q, new_e))
goto fail;

if (elv_register_queue(q))
@@ -722,7 +704,7 @@ static void elevator_switch(request_queu
/*
* finally exit old elevator and turn off BYPASS.
*/
- elevator_exit(old_elevator);
+ elevator_exit(&old_elevator);
clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
return;

@@ -731,14 +713,11 @@ fail_register:
* switch failed, exit the new io scheduler and reattach the old
* one again (along with re-adding the sysfs dir)
*/
- elevator_exit(e);
- e = NULL;
+ elevator_exit(&q->elevator);
fail:
q->elevator = old_elevator;
elv_register_queue(q);
clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
- kfree(e);
-error:
elevator_put(new_e);
printk(KERN_ERR "elevator: switch to %s failed\n",new_e->elevator_name);
}
@@ -762,7 +741,7 @@ ssize_t elv_iosched_store(request_queue_
return -EINVAL;
}

- if (!strcmp(elevator_name, q->elevator->elevator_type->elevator_name)) {
+ if (!strcmp(elevator_name, q->elevator.elevator_type->elevator_name)) {
elevator_put(e);
return count;
}
@@ -773,7 +752,7 @@ ssize_t elv_iosched_store(request_queue_

ssize_t elv_iosched_show(request_queue_t *q, char *name)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
struct elevator_type *elv = e->elevator_type;
struct list_head *entry;
int len = 0;
diff -urpN -X a/Documentation/dontdiff\
a/block/ll_rw_blk.c b/block/ll_rw_blk.c
--- a/block/ll_rw_blk.c 2005-11-27 14:46:09.000000000 -0800
+++ b/block/ll_rw_blk.c 2005-11-24 14:45:51.000000000 -0800
@@ -1612,8 +1612,7 @@ void blk_cleanup_queue(request_queue_t *
if (!atomic_dec_and_test(&q->refcnt))
return;

- if (q->elevator)
- elevator_exit(q->elevator);
+ elevator_exit(&q->elevator);

blk_sync_queue(q);

diff -urpN -X a/Documentation/dontdiff\
a/block/noop-iosched.c b/block/noop-iosched.c
--- a/block/noop-iosched.c 2005-11-27 14:46:09.000000000 -0800
+++ b/block/noop-iosched.c 2005-11-24 20:21:15.000000000 -0800
@@ -19,7 +19,7 @@ static void noop_merged_requests(request

static int noop_dispatch(request_queue_t *q, int force)
{
- struct noop_data *nd = q->elevator->elevator_data;
+ struct noop_data *nd = q->elevator.elevator_data;

if (!list_empty(&nd->queue)) {
struct request *rq;
@@ -33,14 +33,14 @@ static int noop_dispatch(request_queue_t

static void noop_add_request(request_queue_t *q, struct request *rq)
{
- struct noop_data *nd = q->elevator->elevator_data;
+ struct noop_data *nd = q->elevator.elevator_data;

list_add_tail(&rq->queuelist, &nd->queue);
}

static int noop_queue_empty(request_queue_t *q)
{
- struct noop_data *nd = q->elevator->elevator_data;
+ struct noop_data *nd = q->elevator.elevator_data;

return list_empty(&nd->queue);
}
@@ -48,7 +48,7 @@ static int noop_queue_empty(request_queu
static struct request *
noop_former_request(request_queue_t *q, struct request *rq)
{
- struct noop_data *nd = q->elevator->elevator_data;
+ struct noop_data *nd = q->elevator.elevator_data;

if (rq->queuelist.prev == &nd->queue)
return NULL;
@@ -58,7 +58,7 @@ noop_former_request(request_queue_t *q,
static struct request *
noop_latter_request(request_queue_t *q, struct request *rq)
{
- struct noop_data *nd = q->elevator->elevator_data;
+ struct noop_data *nd = q->elevator.elevator_data;

if (rq->queuelist.next == &nd->queue)
return NULL;
diff -urpN -X a/Documentation/dontdiff\
a/include/linux/blkdev.h b/include/linux/blkdev.h
--- a/include/linux/blkdev.h 2005-11-27 14:46:38.000000000 -0800
+++ b/include/linux/blkdev.h 2005-11-24 14:45:51.000000000 -0800
@@ -316,7 +316,7 @@ struct request_queue
*/
struct list_head queue_head;
struct request *last_merge;
- elevator_t *elevator;
+ elevator_t elevator;

/*
* the queue request freelist, one for reads and one for writes
-
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